Performance and Complexity Comparison of Adaptive Loop-Bandwidth Tracking Techniques

This paper analyzes the performance and complexity of state-of-the-art adaptive scalar tracking techniques used in modern digital global navigation satellite system (GNSS) receivers. Ideally, a tracking channel should be able to adjust to both noisy and dynamic environments for optimal performance. Precision and robustness define the performance of the tracking. The difference between the square root of the Cramer-Rao bound (CRB) and the average tracking jitter at the discriminator's output determines the precision of the tracking, whereas the speed of the response specifies the robustness of the tracking in high dynamic scenarios. The amount of operations required to implement a robust tracking technique indicates the complexity of the algorithm. The fast adaptive bandwidth, the fuzzy logic, and the loop-bandwidth control algorithm adaptive tracking techniques are first analyzed and evaluated in a software receiver. Second, these techniques are implemented in an open software interface GNSS hardware receiver for testing in simulated scenarios with real-world conditions. The scenarios represent different dynamics and noise cases. The results show the loop-bandwidth control algorithm's advantage over adaptive loop-bandwidth techniques while preserving good tracking performance and low complexity.